The brainchild of Shanghai-based developers Alex Zhu and Luyu Yang, the social video app allows users to lip-sync and share 15 seconds of a song. Originally rolled out in China, Japan and the United States in October 2014, American audiences – namely, teenage girls – immediately took to the platform, launching it to #1 on the App Store charts in 2015 and keeping it in the Top 40 ever since.

But the real reason Perry and pop heavyweights like Lady Gaga, Zedd and Selena Gomez are courting "Musers" is because of people like Ariel Martin ("Baby Ariel") and Jacob Sartorius – homegrown Musical.ly stars. When Baby Ariel, age 16, and Sartorius, age 14, make Musical.lys of "Chained to the Rhythm" or "Million Reasons," their 15-second music videos are shared with roughly 17 million other users.

The landscape of music discovery is diversifying, a trend started by the now-dead video-sharing app Vine. On Vine, hits like Fetty Wap's "Trap Queen" and Drake's "Hotline Bling" gained even more traction from the humorous video memes made by users. More recently, Twitter and Instagram memes — both video and otherwise — turned Rae Sremmurd's "Black Beatles" and Migos' "Bad and Boujee" into long-running Number One hits. With Vine's proven history of minting new pop stars (Shawn Mendes, Ruth B) and huge hits ("Watch Me (Whip/Nae Nae)"), Musical.ly is positioned to be pop's new gatekeeper.

"What we are seeing right now is an amazing number of Musers discovering new music and then going to Spotify and Apple Music," says Alex Hoffman, Musical.ly's North America president.

Last October, Musical.ly launched its #NextWave program to take advantage of that trend. Each month, a group of 15 songs by (mostly) emerging artists are selected. The song that generates the most Musical.ly videos in a month is promoted on the app's homepage, like a custom publicity campaign. #NextWave focuses on new acts, but occasionally includes indie bands with small followings. February, for example, features a track by Ra Ra Riot up against songs by lesser-known artists like Darline and Tiffany Houghton.

So far, #NextWave winners include Anne-Marie's "Alarm," Charli XCX's "After the Afterparty" and Timeflies' "Gravity." Charli XCX and Timeflies' may have had an edge since both acts already had big fan bases. But in the case of a lesser-known artist like Anne-Marie, the #NextWave win helped her crack the Top Three on Billboard's Bubbling Under chart.

Musical.ly's ability to springboard new music and artists has yet to reach the heights of Vine, which churned out global phenomenons like singer-songwriter Shawn Mendes and dance crazes like Silentó's "Watch Me" and I Heart Memphis' "Hit the Quan," but record companies are taking notice early on how to better benefit from the app's influence. The service has launched First Listen, a new initiative that promotes music premieres from major label artists.

Musical.ly's first premiere offered Musers an advance 15-second clip of Selena Gomez and Kygo's hit "It Ain't Me" ahead of the song's full release. This week's First Listen was a premiere of Alessia Cara and Zedd's "Stay." As of press time, the tag #StayFirstListen is one of the Top Five trends on the app.

Hoffman says record companies are more willing to license 15 seconds of a song, which fosters a symbiotic relationship between record labels and the app. More recently, the app's executives have held meetings with many of the biggest streaming services about potential partnerships to make the music discovery capabilities more seamless.

Even the most famous Musers are taking advantage early of what the platform is capable of. Martin signed with high-powered agency CAA last year, who will represent the singer in all facets of her career. Sartorius has already leveraged his massive following into a bona fide music career. He released his debut EP The Last Text in January. His singles "Sweatshirt" and "Hit or Miss" both landed in the Billboard Hot 100.

"I was looking at people like Shawn Mendes who had transferred from social media to becoming a mainstream recording artist," Sartorius tells Rolling Stone of his inspiration for pursuing music. He had performed onstage as a kid in musicals and had always been complimented on his voice. "I really enjoyed the comedy stuff, but it was really great to transfer into music. It's something I've always had a passion for."

Martin ("Baby Ariel") hopes her Musical.ly popularity will lead to an acting career. She already has everything from an anti-bullying platform called the Baby Ariel Movement to her own line of lipsticks. Hoffman singles out Ariel's fame, comparing the type of attention she gets at public events to Beatlemania.

"My life has changed dramatically," Ariel says since joining Musical.ly. "I'm making videos every single day."

As Musical.ly grows, the developers and executives are looking for ways to branch out and avoid stagnation. They have launched a second app called Live.ly where users can livestream their lives and profit off the viewership with a real-time Virtual Gift System that others can donate to. Hoffman sees Musical.ly as shifting significantly in 2017, becoming less of a video-sharing app and more of its own social network.

"We really see Musical.ly as an entertainment social network," he says, noting that Musers already take advantage of the in-app messaging system to communicate with one another – a unique feature that Vine did not have. "There are other platforms out there that are really good for entertainment, and there are other platforms out there that are really good social networks. We see ourselves at the intersection of both."

The allure of indie stars like Ariel and Sartorius, much like that of Vine stars (like Mendes, Nash Grier and Cameron Dallas) can be attributed to a multi-platform engagement. Turning Musical.ly into a more immersive social experience could make it a one-stop platform. Already, Musical.ly's numbers suggest it rivals the Big Three of Instagram, Twitter and Snapchat.

Now with big pop stars drawing mainstream attention to the app, Musical.ly's main concern is that when the adults come – as they always do – they don't spoil the vibe.